At some point, another group settled on twin planets that became known as Romulus and Remus. While Romulus was a Class M planet, Remus was a harsh planet notable only for its dilithium deposits. Once settled, the two worlds became the foundation of an interstellar empire that expanded to many worlds, reaching across some of the Alpha Quadrant. Eventually that power came to be known as the Romulan Star Empire. (TNG: "Gambit, Part I", "Gambit, Part II"; Star Trek Nemesis)

In 2387, a star close to Romulus went supernova. AmbassadorSpock attempted to prevent the supernova from striking the planet using red matter, but he was unsuccessful and Romulus was destroyed. A mining vessel, the Narada, survived and was captained by Nero, who exploited the black hole's creation of a time warp into the past to attack Spock's home planet of Vulcan in revenge and planned to destroy all planets of the Federation so that Romulus could be "free" and possibly conquer everywhere else. The first part of Nero's plan was mostly successful as Vulcan and most of the Vulcan species was destroyed. However, the Narada and its crew were destroyed in the Battle of Earth by the crew of the Enterprise led by the James T. Kirk of the new timeline. (Star Trek)

After the Treaty of Algeron went into effect, the Romulans retreated into political and social isolation from the Federation. In late 2364, an unprovoked attack on a Romulan outpost near the Federation neutral zone occurred. The Romulans initially suspected the Federation had executed the attack but it was later learned that the Borg may have been responsible. This event marked the end of Romulan political isolationism with the Federation. (TNG: "The Neutral Zone")

In keeping with their xenophobic and arguably racist attitudes, the Romulans tend to conquer species rather than form alliances with them, and individual Romulans tend to treat other species with varying degrees of disdain.

That did not prevent them from employing diplomacy when it suited their purposes. Soon after their emergence from a century of isolation in the mid 2260s, they had established at least two embassies with the Federation. One such embassy was a three-way endeavor on the planet Nimbus III, along with the Klingon Empire, and the other was on Earth itself. (Star Trek V: The Final Frontier; Star Trek VI: The Undiscovered Country)

Klingons and Romulans once shared an alliance for a number of years, beginning in the 2260s. Over the years, a number of incidents, including the Khitomer Massacre, led the Klingons to develop a deep-seated hatred for the Romulans, and the Romulans were arguably the species that Klingon society in general despises most of all. (TOS: "The Enterprise Incident"; TNG: "The Neutral Zone")

One common saying among the Romulans was "Never turn your back on a Breen." While this statement could be taken as partially humorous and not in itself indicative of hostilities between the two species, the Breen Thot's apparent condition that the Breen be given Romulus in exchange for their help in the Dominion War suggested there was some degree of unfriendly history between the two. (DS9: "By Inferno's Light", "Strange Bedfellows")

The species that Romulans seem to dislike most, however, were Vulcans, and this feud goes back many centuries. The two powers once fought in a war that lasted 100 years which was ignited due to a misunderstanding created by one of Q's self-destructive stunts. (VOY: "Death Wish")

The two species remained distrustful of one another for an incredibly long time, but some Romulans grew tired of this, and a grassroots movement for reunification of the two species was active for a time on Romulus. It was generally assumed that after the split, Romulans and Vulcans were unaware of their common ancestry until the 23rd century. (ENT: "Kir'Shara"; TOS: "Balance of Terror")

The exact date, or even a reasonable timeframe, of the Vulcan/Romulan split is very unclear, though it certainly happened some time after Surak's teachings were introduced, which, on the Earth calendar, would be the 4th century AD or so.

Due to their shared ancestry, Vulcans and Romulans possessed very similar physiology, including varied skin color. Romulans had pointed ears, eyebrows that were arched and up-swept, and copper-based blood that appeared green when oxygenated in the arteries, or copper or rust-colored when deoxygenated in the veins. (Star Trek Generations) Most Romulans had two brow ridges above the bridge of their nose, forming a V-shape on the forehead. However, a minority of Romulans lack these ridges, making them outwardly indistinguishable from Vulcans.

These "browless" Romulans were predominant in the 23rd century, (TOS; Star Trek VI: The Undiscovered Country) but were not seen in the 24th century en masse until Nero and his crew in Star Trek. No in-universe explanation has ever been given for the difference in appearance. StarTrek.com suggested that the ridged majority of Romulans were a different race that evolved on Vulcan simultaneously with them. [X]wbm In an interview, Neville Page, the head art designer for 2009's Star Trek had a different explanation. During his work on the movie, he first created a back-story to justify the change their faces had undergone, explaining that as a result of their grief, anger, and general bad-ass persona, the Romulans chose to cut and scar themselves, leaving behind such significant keloids on their foreheads that it eventually wended its way into the gene pool over many years, eventually becoming a natural characteristic of all Romulans and thus creating the distinct difference between them and their Vulcan cousins. [1]

Despite their common ancestry there were also many subtle internal physiological differences between Vulcans and Romulans. Their life signs registered distinctly enough on the scanners of the USS Enterprise in 2268 that officer Pavel Chekov was able to distinguish his crewmate Spock from the crew complement of a Romulan starship, though he did note the difficulty of the task. (TOS: "The Enterprise Incident")

The physical differences between Romulans and Vulcans were evidenced in Dr. Beverly Crusher's failed attempt to treat a Romulan, Patahk, who had suffered advanced synaptic breakdown, with the methods used to treat Vulcans. In fact, it was later determined that the genetic similarities between Romulans and Klingons allowed for the two species to have a compatible ribosome match to effect treatment. (TNG: "The Enemy")

In Romulan society, military/political rank influences social standing. Because Romulans were members of a militaristic civilization, who considered defending the Romulan Empire and their own personal honor of foremost importance, military service and its accompanying rank were decisive factors in determining social eminence. (TOS: "Balance of Terror") However, while the military played an important role in Romulan society, it was the Romulan Senate that controlled the government. (Star Trek Nemesis)

Human clone, Shinzon who was Praetor in 2379 after a coup d'etat, on his throne

By the 24th century, the government of Romulus was dependent upon the Tal Shiar, the Romulan secret police, to maintain order and stability among both civilians and the military. The Tal Shiar was known for its brutal tactics, which included routine kidnapping, torture, and assassination. Many Romulans feared even expressing dissenting opinions in order to not bring the attention of the Tal Shiar. There were also indications that tension existed between the military and the Tal Shiar. (TNG: "Face of the Enemy")

Romulan society was based upon a highly structured caste system. Unlike most of the highly evolved species in the Alpha Quadrant, Romulans still practiced slavery, in this case of the Remans, which they used for slave labor and as shock troops. (Star Trek Nemesis)

Romulans tended to be highly xenophobic, engaging in extended periods of isolationism, and could be perceived as outright racist to other species, believing themselves to be superior. At least some Romulans believed that, one day, the Romulan Empire would rule the entire galaxy. (TNG: "The Neutral Zone", "Data's Day", "The Enemy") According to Miles O'Brien, there was no piece of technology in existence that the Romulans didn't claim they invented before everyone else. (DS9: "Explorers")

The Romulans lacked the rigorous mental disciplines developed by the followers of Surak. Like the Vulcans, the Romulans gave up unrestrained violence as a way of life. However, in the case of the Romulans, this was replaced with a controlled deviousness: as a species, the Romulans were generally thought of as duplicitous, a reputation reinforced by the actions of their government over time. (TNG: "The Neutral Zone")

Reluctance to rely on overt hostility generally lead the Romulans to play a waiting game with their opponents, attempting to manipulate an adversary into breaking – or appearing to break – an agreement so as to give them a solid justification for striking. (TNG: "The Defector", "The Pegasus")

They were also well-known for fearing disgrace over death. (TAS: "The Practical Joker") With this frame of mind, Romulan parents disposed of any newborn carrying birth defects, as the alternative would mean a waste of resources. (TNG: "The Enemy")

The totalitarian nature of Romulan society, in which dissent was often a crime and Romulan security officers masqueraded as citizens, led many Romulans to be extremely paranoid. (TNG: "Unification I")

While many arguably belligerent and militaristic species, such as Nausicaans, Breen, and even Klingons often sold their fighting skills to the highest bidder, Romulans were rarely, if ever, seen involved in such activities. This was possibly due to the apparent superiority complex of most Romulans, many of whom likely found such work beneath them, and who preferred to serve the Romulan Empire in some capacity. However, Miles O'Brien once played a game of tongo with a Romulan mercenary (DS9: "Change of Heart"). In cases of anonymity, they were known for commonly using hired assassins, such as the Flaxians, to conduct their off-world "justice" (DS9: "Improbable Cause").

In the Star Trek prequel comic Star Trek: Countdown, it was explained that it was Romulan tradition that when a loved one died, those who suffered a loss would paint their grief upon their skin. In time, the paint would fade and with it, the period of mourning. Nero and his crew, however, burned their tattoos deep so that they would never fade.

Paul Schneider modeled the Romulans on the ancient Romans, naming the species' homeworlds after the mythical founders of Rome, Romulus and Remus. "It was a matter of developing a good Romanesque set of admirable antagonists that were worthy of Kirk," Schneider related. "I came up with the concept of the Romulans which was an extension of the Roman civilization to the point of space travel, and it turned out quite well." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 34) D.C. Fontana reckoned that Schneider basing the aliens on the pre-existing Roman civilization was the cause for the writer receiving insufficient credit for creating the Romulans. ("Balance of Terror" Starfleet Access, TOS Season 1 Blu-ray) Gene Roddenberry, interested in ancient Rome himself, approved of the initial depiction of the Romulan species. "He loved Paul's having endowed the enemy-Romulans with the militaristic character of the ancient Romans," wrote John D.F. Black and Mary Black. (Star Trek: The Magazine Volume 2, Issue 11, p. 19) Roddenberry's original concept of the Romulans, however, was that they represented 1960s' Chinese Communists. (Star Trek: Nemesis hardback ed., p. xx)

The script for "Balance of Terror" originally implied, by describing the Romulan Bird-of-Prey as an Enterprise saucer section attached to a pair of warp nacelles, that the Romulans had somehow stolen starship components from the Federation. ("Balance of Terror" Starfleet Access, TOS Season 1 Blu-ray)

In common with Gene Roddenberry, the Blacks and D.C. Fontana also appreciated Paul Schneider's invention of the Romulans, the Blacks describing them as, "Villains strong enough and clever enough that the audience would be compelled to believe they were capable of the first move that would lead to the destruction of the Federation." (Star Trek: The Magazine Volume 2, Issue 11, p. 20) Fontana enthused, "They were a wonderful, wonderful enemy [....] to have, because we could talk about them, people had seen them once, and we didn't know a lot about them. They were wonderfully mysterious. They've always been my favorites, actually – right up there, next to the Vulcans [....] Paul did a very good job of, you know, creating this race, ultimately, in the script." Fontana also cited the Romulans' exoticness, their pointed ears and relation to Vulcans as one element of why she liked the Romulans. ("Balance of Terror" Starfleet Access, TOS Season 1 Blu-ray)

Lots of experience with Vulcan ear and eyebrow prosthetics, as worn by Leonard Nimoy in the role of Spock, stood makeup artist Fred Phillips in good stead for dealing with the Romulans in Star Trek: The Original Series. (Star Trek: The Original Series Sketchbook, p. 185) However, the makeup was too impractical for the Romulans to be brought back on a regular basis, with the pointed ears especially bringing about several problems. The cost of manufacturing the ears, which were made from latex, was too enormous for multiple actors in any episode and the manpower required to create the ears and apply them for each individual actor would have gone over the budget. The need for costly actor-specific ears was negated via reusable helmets that were worn by the background Romulans. (Star Trek: Aliens & Artifacts, pp. 41 & 42) "It took a long time for the ears to be put on [....] And you have a large number of extras coming in, that have to have these ears put on. It's very expensive, it's time," commented Denise Okuda. "And so they came up with this ingenious idea of putting helmets on, so you could hide the fact that these actors did not have pointed ears on." ("Balance of Terror" Starfleet Access, TOS Season 1 Blu-ray) The Romulan ears were manufactured by Wah Chang, as were the group's helmets. For both, he charged Desilu Productions US$748.80. Chang invoiced Desilu for this payment on 26 July1966 and the price was paid in the following month (on either 10 or 13 August). (Star Trek: The Original Series Sketchbook, pp. 240-241)

Following their introduction in the first season, the Romulans indirectly appeared in the second season installment "The Deadly Years", via recycled footage of the Romulan Bird-of-Prey, and were temporarily planned to appear themselves in the story that became Season 2's "A Piece of the Action". As such, they were written into the first draft script for the latter of those two episodes, then entitled "Mission Into Chaos". [2]

The Romulans were originally meant to be the villains in Star Trek III: The Search for Spock. In an early story outline that Harve Bennett wrote for the third film, the Romulans discovered that the Genesis Planet had extraordinarily rich dilithium deposits and found Spock's coffin on the planet's surface. Even though they initiated a mining operation, the Romulans encountered trouble with this upon discovering that someone was killing members of the mining team, a mysterious individual who was later discovered to be a regenerated Spock. The story also brought the Romulans in conflict with the Enterprise and its senior officers. Though Kirk realized that the Romulans would become unstoppable if they succeeded with their mining mission, the Romulans were ultimately thwarted by the Starfleet officers, who – having caused the Enterprise to self-destruct to prevent a Romulan boarding party from seizing it – proceeded to capture the Romulan ship for themselves. (Star Trek: The Magazine Volume 3, Issue 8, pp. 29-30)

As Harve Bennett subsequently discussed the story with Leonard Nimoy, the Romulans were at the forefront of their thinking. "Our first conversations were about the Romulans versus the Klingons," Bennett later explained. "I was just looking for a heavy, and in the series – to me – the Romulans seemed to be more dastardly than the Klingons. So it was an error of ignorance." (Star Trek: The Magazine Volume 3, Issue 8, p. 30) Bennett went on to say, "I could have chosen the Romulans, but from my experience seeing all the episodes, I'd never gotten that sense of determination and absolutism that the Klingon episodes have revealed." (audio commentary, Star Trek III: The Search for Spock (Special Edition)DVD/Blu-ray) Moreover, Nimoy persuaded Bennett that the Romulans were less theatrical than the Klingons, so the name of the species that would serve as the movie's villain was switched. The Klingon Bird-of-Prey was intended to have been stolen from the Romulans, but this information was left out of the film. (The Art of Star Trek, pp. 215, 217 & 219)

In the first edition of the Star Trek: The Next Generation Writer'/Directors' Guide, Gene Roddenberry declared that no stories concerning warfare with Romulans would be accepted for the new series. (The Art of Star Trek, p. 92) However, when Roddenberry was attempting to decide upon a new antagonist for regular use on Star Trek: The Next Generation (while considering that the Klingons would no longer appear as recurring villains), writer D.C. Fontana thought of the Romulans. Fontana later recalled, "I sent him a memo, suggesting 'How about the Romulans?' After all, they hadn't been developed all that much in The Original Series, and they were a glamorous, attractive enemy." (Star Trek - Where No One Has Gone Before paperback ed., p. 110) Secure in the knowledge that the TNG viewers had accepted the series as a new version of Star Trek rather than a retread, Roddenberry felt confident enough to bring back the Romulans at the end of the show's first season. (Star Trek: The Next Generation - The Continuing Mission, p. 66) Roddenberry allowed the Romulans to occasionally feature on the new series from then on, but preferred not to use them as the series' primary villains. (Star Trek: The Next Generation 365, p. 036)

The return of the Romulans in the first season TNG episode "The Neutral Zone" was originally discussed as the first of a multi-part story that would have united them with the Federation against the newly discovered Borg. (Star Trek: The Next Generation Companion 3rd ed., p. 60) Writing staffer Maurice Hurley, who wrote "The Neutral Zone" and devised the multi-episode arc, intended for the Romulans to engage in a major battle against a Borg scout ship in the second of the three episodes, planned for the show's second season. The conflict would have culminated in the Romulans destroying the Borg vessel but being completely annihilated themselves. The extermination of the Romulan people would have left a mystery for Picard as to how they had managed to defeat the Borg ship before it had wiped them all out. (Star Trek: The Magazine Volume 1, Issue 23, pp. 15-16) A Writers Guild strike nixed this plan and the introduction of the Borg had to wait. (Star Trek: The Next Generation Companion 3rd ed., p. 60) Nonetheless, the reappearance of the Romulans in "The Neutral Zone" proved the species had lost none of its appeal. (Star Trek: The Magazine Volume 2, Issue 12, p. 21)

For their appearances on Star Trek: The Next Generation, makeup artist Michael Westmore gave the Romulans V-shaped forehead ridges to "compete" with the Klingon redesign introduced in Star Trek: The Motion Picture. (The Art of Star Trek, p. 92) The Romulan ridges also developed from efforts to make them look more menacing than how they had appeared before and physically differentiate them from Vulcans. "From the very first moment they appeared on-screen," Westmore commented, "the viewer had to take them seriously, rather than seeing them as stereotyped villains with pointed ears [....] I devised a forehead that had a dip in the center, and then I hollowed out the temple area. We wanted to stay close to their natural forehead, not making them look Neanderthal, but giving them a built-in sullen expression they couldn't get away from." (Star Trek: The Next Generation 365, p. 068)

It was found that this facial feature complemented a change to the typical Romulan hairstyle that Michael Westmore wanted to introduce. He said of the restyled Romulans, "I gave them a little wedge to the center of the hair on their forehead instead of the Vulcans' straight-across bang." (Star Trek: The Magazine Volume 2, Issue 12, p. 26)

Although the Romulan genealogical tie to Vulcans was unspecified by TNG's writers when the Romulans were brought back – with "Balance of Terror" having introduced the species merely as a likely Vulcan offshoot – the opinion of the show's writers regarding the nature of this relationship had changed by the series' fifth season, as had personnel in the TNG writers' room. Writer Ronald D. Moore, who joined the show in its third season, expressed, "I hated the foreheads on the Romulans. The backstory [established in 'Unification'] was that they were basically the same race, yet somehow the Romulans got these different foreheads at some point." (Star Trek: The Next Generation 365, p. 068) However, the redesigned Romulan makeup remained for not only all future Star Trek productions set in the 24th century but also for when Romulans were featured on Star Trek: Enterprise. The makeup was so extensive that it required the actor's head to be measured during pre-production (at least, it did in the case of Vaughn Armstrong, when preparing to play Telek R'Mor in VOY: "Eye of the Needle"). [4]

For Star Trek VI: The Undiscovered Country, Romulan makeup was designed and fabricated by Richard Snell, though applied by Makeup Supervisor Michael J. Mills. Even though the Romulan facial features on TNG had significantly evolved from those on The Original Series, the Romulans were returned to their earlier form for Star Trek VI. "Basically, this time they had larger, bushier eyebrows and bigger ears," noted Mills. "We stayed away from the forehead pieces and the radically different ears the new TV series has featured and just went with the original look." (Cinefex, no. 49, pp. 42 & 45)

The Romulans were originally to have filled the conspiratorial role that the Son'a play in Star Trek: Insurrection. According to writer Michael Piller in his unpublished reference bookFade In: From Idea to Final Draft, the idea of using the Romulans as major villains in the film was inspired by the fact that the species had been a long-standing enemy of the Federation but had never been featured in a Star Trek movie before. Additionally, Piller and Rick Berman imagined that the story might be set against the threat of a new outbreak of hostilities between the two governments. The Romulans went on to be written into the first version of the film's story. (AOL chat,1998)

As told in Fade In: From Idea to Final Draft, Patrick Stewart criticized even the thought of using the Romulans in Insurrection, believing that they wouldn't make a suitable rival for the follow-up to Star Trek: First Contact. On 1 June1997, he wrote a letter to Rick Berman in which Stewart stated, "I think what dismays me most about the story is the dredging up of the Romulans – a race already unexciting in TNG – as the bad guys. It is revisionist and backward looking in a most disappointing way. After the Borg – the Romulans? Oh, my." On 30 June, Michael Piller responded to this letter with one in which he explained, "We have, from the start, intended to re-invent the Romulans because we agree with you. We’ve been talking about a complete overhaul of their look as well as their character. If it means a great deal to you, I’d personally be willing to change it to another race. Do you have any suggestions?" Stewart responded with another letter, which he sent on 7 July and which confirmed that "the Romulan question" was highly important to him. Stewart continued, "I think it is a deadly idea to have even an 'overhauled' Romulan villain. After the Borg Queen it will look as if we just couldn’t come up with any new bad guys. But we must."

The change to the newly invented Son'a was made "because nobody liked the idea of using the Romulans, ever," said Michael Piller. (The Secrets of Star Trek: Insurrection, p. 14) Regarding the prospect of including the Romulans, Piller clarified, "No-one here felt a great deal of enthusiasm for that decision." (AOL chat,1998) However, Eric A. Stillwell, who contributed to the making of Insurrection as a production associate and script coordinator, believed that the Romulans should have been used, saying, "I think this would have had a greater dramatic impact than introducing an entirely new group of bad guys." He also noted about the exclusion of the Romulans, "I think that was a mistake." [5]

One of the first concepts in the writing of Star Trek Nemesis was to centrally feature the Romulans. A primary advocate for this choice of villain was writer John Logan – a big fan of the species and "the lethal machinations" characteristic of the group. "For a writer, the malicious subtlety of the Romulans," remarked Logan, "offers great opportunities; the cleverness and formality of their language must suggest that they are simultaneously a deadly political foe and a noble, ancient race. Besides, I had just finished working on Gladiator and was in a classical frame of mind. The serpentine rhythms of the language we created for the Roman Empire in that movie were good practice for writing the august and treacherous Romulans." (Star Trek: Nemesis hardback ed., pp. xvii-xviii) Logan also enthused, "I was delighted with the chance to get to play with the Romulans, and I don't think they've quite been explored enough [....] For me the Communist Chinese is a really interesting world that was never fully explored, certainly in the movies, and not even as much as I would have liked in the series, except for individual episodes. I've always found that sort of Byzantine structure of Chinese Communism very interesting and very provocative, and lethal in a way I never found the Klingons. There is so much duplicity and mendacity and cleverness in the way the Romulans move through their world with very strategic chess moves. And also they are an old and ancient race, like the Vulcans, so they have gravitas to them, which I find very interesting." (Star Trek: The Magazine Volume 2, Issue 2, pp. 11-12)

John Logan doubting that the Romulans wouldn't mine dilithium for themselves was a strong influence on the creation of the Remans. "It seemed obvious to me," he said, "that the Romulans would subjugate some other race to dig dilithium for them. Much too messy for our pristine and elegant Romulans." As an homage to Gene Roddenberry's original conception of the Romulans as Chinese Communists, Logan and the other writers of Nemesis made all the Romulan and Reman names in the film of ancient Chinese descent. (Star Trek: Nemesis hardback ed., p. xx)

Although the Remans are clearly the main villainous species in Nemesis, Rick Berman was repeatedly reported as stating, in an interview on a UPN station local to Los Angeles, that the Romulans would be the major villain in the film. [6][7] In Star Trek: Communicator issue 131, he clarified, "What I said was that we would be seeing the Romulans in this movie, which we are, but I did not necessarily say that they were going to be our main villains." [8] In Star Trek: The Magazine Volume 1, Issue 23 (p. 10), he further hinted about the Romulans, "They are part of the villainy, but not in the way that some might think!"

Eric Stillwell was puzzled upon hearing a rumor that the Romulans might be involved in Nemesis at all. He later commented, "I thought [that] was odd after we were asked to remove the Romulans from the original story in Insurrection." [9]

Before the release of Nemesis, Rick Berman additionally remarked, "I'm sure you can expect a fresh, updated look for the Romulans [....] I think there will be some surprises as to what the Romulans will look like." [10] As it was, the Romulan designs used in the film were much as they had been in the preceding series. These similarities not only included their makeup but also stemmed to the production design of their ships, with Production Designer Herman Zimmerman saying, "The Romulans have been kind of an art deco culture and that's what you see [in Nemesis], echoes of 1930s geometry in architecture, just turned sideways." [11]

Applying the Romulan prosthetics for Nemesis regularly took four hours. "I had a forehead prosthetic that they stuck to my head," reported Donatra actress Dina Meyer. "The morning make-up routine consisted of me going into hair and getting my head wrapped – they make your hair all pin-curled and they put your head in a wig cap, so all your hair is pulled off your face. Then you go to the make-up trailer, where they attach the prosthetic forehead and prosthetic ear tips and then they pile on the make-up. They need a spatula to put it on, it's so thick." (Star Trek Monthly issue 100, p. 23)

Because "Balance of Terror" had established Starfleet's first confirmed visual contact with the Romulans as being in 2266, it was somewhat difficult for them to appear on Enterprise, that prequel series primarily being set in the 2150s. The show's producers wanted to include Romulans in the series, despite the risk of contaminating Star Trek canon, ever since the series began. (Star Trek: Communicator issue 135, p. 23)

Some initial consideration was given to making unnamed aliens in ENT: "Silent Enemy" actually be Romulans. André Bormanis, a writing staffer who wrote that episode, explained, "I wondered whether they might be Romulans until we decided to do a CGI alien effect [for the aliens themselves]. I think the technology of their ship, though, was too sophisticated for Romulans in this era, so that argued against making them Romulans too." [12]

The interest in seeing the Romulans on the series of Enterprise continued, however. "We have major continuity issues with them," observed Executive Producer Brannon Braga, at the end of the show's first season. "We would very much like to do Romulans, but a) we don't know quite how yet, and b) since the new movie [Star Trek Nemesis] deals with Romulans, we want to give them some breathing room. We'll do them eventually, but not right away." (Star Trek: Communicator issue 139, p. 29) Intense speculation regarding whether the Romulans would appear in the series was stirred up at the end of Season 1. (Star Trek: Communicator issue 145, p. 24)

In fact, just prior to the release of Star Trek Nemesis, the Romulans seemed to have disappeared. At the time, John Logan rhetorically asked, "Why isn't anyone using them?" Reflected Jack Donner, "To a great deal they have been ignored. They haven't paid that much attention to them [in recent series]. There have certainly been episodes that dealt with Romulans, but nothing like the Klingons, Cardassians and Ferengi." (Star Trek: Communicator issue 137, pp. 46 & 53)

In Star Trek: Communicator issue 137 (p. 85), Rick Berman predicted, "I would [...] not be surprised that, within the next six to twelve months, we will have our first run-in with Romulans [....] I [...] think we will undoubtedly be running into Romulans at some point." However, Berman made these statements without the writing staff of Enterprise having discussed the species appearing on the series nor the art department doing any design work related to the Romulans. [13][14] Responding to the news, André Bormanis remarked, "If that's the case, I'm looking forward to it." [15]

One possibility, considered at around the end of the first season, was whether John Logan would be able to write the script for the Romulans' appearance on Enterprise, which then began to be a likely option for the show's second season. "Yeah, he would love to do that, and we would love to give him that chance," announced Rick Berman. "It's all going to have to do with his time – he has three huge movies that he is working on now. We'll see what happens." In the same interview, Berman went on to outrightly dismiss the chance that Romulans could show up in the first season. (Star Trek: Communicator issue 138, p. 20)

Despite the second season installment "Minefield" initially excluding the Romulans and its premise being a story set entirely on the hull of Enterprise, the plot evolved to include the Romulans. "The idea that the attacking aliens would be Romulans came out a little later, during the story break process," Brannon Braga recollected. "We needed to be true to continuity and this was a way to do it." (Star Trek: Communicator issue 145, p. 24) Braga was happy that this portrayal of the Romulans seemed to come at an appropriate time, commenting, "I think it's cool that on Star Trek Nemesis you can see the Romulans of Picard's time, and at the same time you're seeing the early encounters with them on Enterprise; there's great synergy there." (Star Trek Monthly issue 99, p. 8)

At a convention in Minneapolis held on the second weekend of July 2002, Connor Trinneer conceded that, although he did not know any specifics about the Romulans making a return appearance on Enterprise, such an appearance was very possible, saying he "wouldn't be surprised" by it, at all. [16] It was merely days later, on Tuesday 16 July2002, that Brannon Braga finally announced the upcoming Season 2 Romulan episode, hinting, "I think I can say without getting into too much trouble that very early in the season we will have our first brush with the Romulans. ... Capt. Archer will have a very lethal brush with the Romulans early on." [17] On several occasions, Braga also tried to give assurances that the continuity with the Romulans was "airtight." [18][19]

Despite featuring heavily in "Minefield", Reed actor Dominic Keating revealed to fans, “I have NO idea who they are!” [20]

Prior to the initial airing of Enterprise's season 2 finale "The Expanse", many fans at first incorrectly speculated that the Romulans were responsible for the attack on Earth depicted in that episode – thought to be the initial volley in the Romulans' previously established war with Earth – and would be the focus of the series' third season, rather than the multi-specied Xindi. Brannon Braga was of the opinion that, had the Romulans indeed been used, they would have become "old" and less satisfying during the relatively lengthy course of the third season arc. He also stated that this did not exempt the species from appearing in that season, in which they nevertheless ultimately did not feature. (Star Trek: Communicator issue 145, p. 32)

During development of the 2009 film Star Trek, the writers of the movie's script, Alex Kurtzman and Roberto Orci, chose the Romulans as the villains because the film was a continuation of Spock's story from "Unification".[21]J. J. Abrams said "What was interesting to me was that it wasn’t the Klingons. That's what you expect and it was fun to use the Romulans the way we did," referring to their premature appearance in Kirk's life being a clear marker of divergence from the prime reality. "Part of the fact is that they hadn’t seen them for so many years, so that it immediately breaks, for anyone who knows, the rules of Trek to start the movie and have Romulans crossing paths with Starfleet."[22] Orci and Kurtzman focused more on writing the Romulans in later drafts of the screenplay. (Star Trek Magazine issue 146, p. 27)

Romulan prosthetics for the film Star Trek were at first arranged to be the purview of Proteus FX Makeup Effects Supervisor Barney Burman. "I did some early designs for the Romulans in my shop, but when my workload became too heavy, I hired Joel Harlow to come in and handle them. We all decided it would be best if Joel took over the task of creating the Romulans on set close to [Director] J.J. [Abrams] so he could see and direct their progress each day. We set up a makeup trailer for the Romulans, and Joel hired a crew of people to work on that and just did a fantastic job." (Star Trek Magazine issue 155, p. 57) This makeup crew, called Joel Harlow Designs, sculpted and designed Romulan ear and forehead prosthetics. A total of forty main Romulan characters were created to appear in the movie, a process that started with lifecasts for each actor. (Star Trek - The Art of the Film, p. 37) Harlow himself remembered, "J.J. did not want to see any hair lace in the wig applications, so we made the entire forehead and eyebrows as one piece, with hair punched into the silicone before application. I wanted to give the Romulans an animal look, so we widened their nose bridge and did some interesting stuff with their brows – but nothing so extreme that you couldn't believe they were real." (Cinefex, No. 118, pp. 46 & 47) After the individual prosthetic pieces were crafted and prepared for filming, Harlow's team also applied the prosthetics. The Romulan makeup designs from the same film incorporated tattoos that were made to look tribal. (Star Trek - The Art of the Film, p. 37)

Alex Kurtzman and Roberto Orci admitted that, even in the alternate reality, not all Romulans are necessarily bald. (Star Trek Magazine issue 149, p. 13) In reality, baldness of Nero and his crew was used to set the Romulans apart, physically, from the Vulcans in the movie, due to both species having slanted eyebrows and pointed ears. (Star Trek Magazine issue 155, p. 57)

Casting Director April Webster was at first very puzzled as to how to cast the Romulans in the film. "I had no idea what we were going to do with the Romulans," she conceded. However, an influence on overcoming this challenge was the fact that the rest of the movie's cast incorporated a wide variety of people, with different skin colors and ages. Webster continued about the Romulans, "We just made a list of the most interesting actors we could think of who could match up and hold their own in a scene with [Nero actor] Eric Bana." (Star Trek Magazine issue 144, p. 30)

There were subtle alterations made to the Romulan prosthetics (at least for the Nero character) before filming, making it easier to perform on long shooting days. Eric Bana stated, "The prosthetics only underwent very minor changes, just for comfort and actability. Sometimes you make a really tiny change with the prosthetic, or the glue, or where it's attached, and it can really make a difference to your ability to convey expression. We had a few goes at that in pre-production to get that right." By the time a week of filming had gone by, Bana found the new Romulan facial appearance "began to look completely normal to me, and regular humans started to look weird!" (Star Trek Magazine issue 146, p. 24) On the other hand, according to Star Trek Magazine issue 146 (p. 24), the Romulans on set seemed distinctly intimidating.

The Romulans proved extremely popular amongst Star Trek fans. "When my episode first aired," remarked Jack Donner, regarding "The Enterprise Incident", "I got a letter from a fan named Lori Carlson in Denver, Colo. She was the president of the Leonard Nimoy/Vulcan club there, but she wrote to me and said that the club was switching their interests around. And now there are Romulan fan clubs all over the place – in Michigan, and Bakersfield, California, to name just a few." (Star Trek: Communicator issue 137, p. 53) The Romulans had become fan favourites by the end of TNG's first season. (Star Trek: The Next Generation - The Continuing Mission, p. 66)

Star Trek novel scribe Susan Schwartz also approved of the Romulans. "I personally like the combination of raw intellect and harnessed ferocity, with all that history underlying it," she explained. "With the Romulans, I like the plotting, too, and the honor and the irony. I've always liked them, from the time I saw Marc Lenard's face in 'Balance of Terror' and realized what they were swiping from." [23]

A group of Romulans appeared in a 1995 television commercial for a Christmas ornament of the Romulan Warbird, made by Hallmark. Makeup for these Romulans was provided by Michael Westmore's makeup team. (Star Trek Monthly issue 9, p. 50)

In Duane's novel The Romulan Way, Vulcan society becomes polarized by their first encounter with an alien species - Orionpirates attempting to invade their world. S'task, a Vulcan poet and former disciple of Surak, argues in favor of strength, while Surak's increasingly popular beliefs favor pacifism and logic. To avert civil war between the two factions, S'task leads his followers on a mass migration. As part of their exodus, they intentionally invent a new culture and a new language. They refer to themselves as the Rihan, which means "the Declared," in their new language. Likewise, they named their new homeworlds ch'Rihan ("of the Declared") and ch'Havran ("of the Travelers"); the names Romulus and Remus were pinned on their worlds by the Federation exploration vessel that first entered their star system - according to Duane, those Rihannsu who learned about the names used for them by the Federation were puzzled, more than anything else, by the myth from which the names originated (twin brothers being raised and suckled by a wolf).

In the Vulcan's Soul trilogy, the Romulans' ancestors left Vulcan as a contingency plan approved by Surak, should the wars on Vulcan have completely destroyed their civilization. The eagle emblem was inspired by a huge bird native to Romulus that clutched eggs in its talons.

The comic book Star Trek: Countdown and the video game Star Trek Online depict the lead up and the aftermath of Romulus' destruction, primarily caused by the Romulan Senate ignoring Spock's warnings about the supernova, and the Vulcan Science Council's refusal to lend them red matter. In spite of this, Federation-Romulan relations had been improving and Romulan citizens had become less xenophobic, as indicated in the ending of Star Trek Nemesis. After the supernova, Federation aid is either welcomed or met with suspicion and even hostility, while the Klingon Empire seizes the opportunity to conquer Romulan territory. Despite continuing in-fighting between the survivors, a new capital called Rihan is established on Rator III. The Romulans are playable characters in the 2013 Online expansion pack Legacy of Romulus. The playable Romulans and Remans are members of a splinter Republican faction on New Romulus led by D'Tan.

Romulan religious beliefs vary in non-canon sources.

The Way of D'era sourcebook states the Romulans believe in the Way of D'era. Tellus, an enemy of Surak, taught that the inhabitants of Vorta Vor – the mythological world mentioned in Star Trek V: The Final Frontier – had visited the Vulcans and inspired them to become the supreme rulers of the galaxy. This explains the superiority complex and their hatred for Vulcans, whom they see as traitors.

In Duane's Rihannsu series, the Romulan religion is animistic, born out of the apparently innocuous comment, made by one philosopher aboard the ships outbound from Vulcan, that "things notice" - i.e., that lost objects remain lost as long as you are looking for them, then reappear as soon as you stop looking. From this observation grew an entire theological colloquy, and eventually a religion based on worship of the classical elements of fire, air, water, earth and the "Archelement" which oversees the others.

There are also various, conflicting explanations for the Romulans' lack of telepathic ability:

In Duane's My Enemy, My Ally, Spock explains that the Romulans left Vulcan before the mental disciplines of Vulcan were fully developed, and genetic drift has caused them to lose any latent ability they might have;

This is contradicted in Duane's sequel The Romulan Way, which explains that a number of trained telepaths accompanied the Rihannsu ships leaving Vulcan, but eventually died as a result of having to use their Psionic abilities to propel the ships from one star system to another; because it required a group of telepaths to train new adepts, the Rihannsu's telepaths died at a faster rate than they could be replaced; according to this novel, Vulcans in the 23rd century believe that the Romulans still possess the raw potential to produce telepaths, but will never do so without hands-on instruction from Vulcan adepts;

According to the Vulcan's Soul trilogy, the Romulans rejected the telepathy of the Vulcans and slaughtered or enslaved the telepaths among themselves during their exodus from Vulcan: these telepaths became the Remans. This explains why no Romulan displays telepathic skills in canon, while some Remans, such as Shinzon's Viceroy, do.

In Nero, the titular character takes a drug that enables him to meditate, and to develop the skills to communicate telepathically, without mind melding.

The Way of D'era explains that the Romulans lack the physical strength of the Vulcans because they no longer live on a harsh environment. Killing Time shows Romulans slightly adverse to the effects of pon farr.

The alternate reality Romulans themselves debut in the two-part "Vulcan's Vengeance" story from IDW Publishing's Star Trek comic book series. It is stated the Senate approved of Nero's actions. A group of Vulcans led by Sarek infiltrate Romulus and attempt to avenge their homeworld by detonating red matter recovered from Vulcan. Spock convinces his father the plot is a mistake, and prevents the detonation. He and his fellow crew members are allowed to return as a "fair exchange" while the Senate keeps the red matter. They also gain the Narada's schematics. Later in the series, Section 31 allies with the Romulans to start a war with the Klingons, in a successful ploy to regain the last piece of red matter.